metadata.json from "Using Flex Templates" docs results in syntax error on build

[tjwebb]

In which file did you encounter the issue?

https://github.com/GoogleCloudPlatform/python-docs-samples/blob/master/dataflow/flex-templates/streaming_beam/metadata.json

Did you change the file? If so, how?

git diff metadata.json
diff --git a/dataflow/flex-templates/streaming_beam/metadata.json b/dataflow/flex-templates/streaming_beam/metadata.json
index 029a505d..7dfb3242 100644
--- a/dataflow/flex-templates/streaming_beam/metadata.json
+++ b/dataflow/flex-templates/streaming_beam/metadata.json
@@ -5,7 +5,7 @@
     {
       "name": "input_subscription",
       "label": "Input PubSub subscription.",
-      "help_text": "Name of the input PubSub subscription to consume from.",
+      "helpText": "Name of the input PubSub subscription to consume from.",
       "regexes": [
         "[a-zA-Z][-_.~+%a-zA-Z0-9]{2,}"
       ]
@@ -13,7 +13,7 @@
     {
       "name": "output_table",
       "label": "BigQuery output table name.",
-      "help_text": "Name of the BigQuery output table name.",
+      "helpText": "Name of the BigQuery output table name.",
       "is_optional": true,
       "regexes": [
         "[^:]+:[^.]+[.].+"

Describe the issue

Following docs: https://cloud.google.com/dataflow/docs/guides/templates/using-flex-templates#running_a_flex_template_pipeline

results in this error using the provided metadata.json (linked above):

gcloud beta dataflow flex-template build $TEMPLATE_PATH \
>     --image "$TEMPLATE_IMAGE" \
>     --sdk-language "PYTHON" \
{
>     --metadata-file "metadata.json"
ERROR: gcloud crashed (ValueError): Invalid template metadata. Parameter helpText field is empty. Parameter: <ParameterMetadata
 label: 'Input PubSub subscription.'
 name: 'input_subscription'
{
 regexes: ['[a-zA-Z][-_.~+%a-zA-Z0-9]{2,}']>

[davidcavazos]

Hi @arvindram03, is the helpText parameter only supported in camelCase? If so, can we support snake_case as well for Python metadata files?

[davidcavazos]

Thank you for filing this, the fix has been merged :)

Apparently, only camelCase was supported for the metadata file, so we've updated the docs and code samples.